A conventional percussion instrument with a foot pedal, referring to FIG. 1, mainly comprises a foot pedal 1 which is mounted a pair of upright bracing posts 2 at the front side, a hexagonal axle 3 is hinged transversely on an upper side of the bracing posts 2, a chain wheel 4 is run through by the axle 3, a drumstick holder 5 is located at one side of the chain wheel 4 and a drumstick 6 is fastened to the drumstick holder 5. The foot pedal 1 has a rear side hinged on a rear end of a pedal 7. The pedal 7 has a front end connected to a lower end of a chain 8. The chain 8 has an upper end containing a plurality of chain links engaged with chain teeth formed on the circumference of the chain wheel 4. The last chain link at the upper end of the chain 8 is run through by a pin 9 to engage with the chain wheel 4. The pedal 7 is positioned in an inclined manner with the front end at a higher elevation.
When in use, a performer steps the pedal 7 with a foot to draw the chain 8 downwards and drive the chain wheel 4 to turn, the drumstick holder 5 is turned at the same time to drive the drumstick 6 to strike the head of a drum (not shown in the drawing).
The greater the gradient of the pedal 7, the stronger the force the drumstick 6 striking the head of the drum, and louder and clearer sound of the drum is generated. On the other hand, the smaller gradient of the pedal 7 generates a smaller sound of the drum. Hence by adjusting the gradient of the pedal 7, the striking force of the drum can be changed according to different musical composition. Adjustment is generally accomplished by altering the pendent range of the chain 8 so that the gradient of the pedal 7 can be changed. However, due to the last chain link at the upper end of the chain 8 is fastened to the chain wheel 4 through the pin 9, adjusting the gradient of the pedal 7 has to disassemble the pin 9 and to change the pin hole at a different location where the pin 9 runs through the chain wheel 4 so that the force of striking the drum can be changed. Such a process is awkward and troublesome.